Plasticity control for brick machines



Feb. 1, 1944. LOTZ' ETAL 2,340,673

PLASTICITY CONTROL FOR BRICK MACHINES Filed May 4, 1942 4 Sheets-Sheet 1 I I M IZZZ/Js yaamzmufz w Feb. 1, 1944.

A. F. c. LOTZ EIAL PLASTICITY CONTROL FOR BRICK MACHINES Filed May 4, 1942 4 Sheets-Sheet 2 l u u Feb. 1, 1944.

A. F. c. LOTZ ETAL I 2,340,673 PLASTICITY CONTROL FOR BRICK MACHINES Filed May 4, 1942 4 Sheets- Sheet s q u g v a a F 1,1944.- A. F. c. Lam HAL 2,340 613 PLAS TICITY CONTROL FOR BRICK MACHINES Filed May 4, 1942 '4 SheetsSheet 4 Patented Feb. 1, 1944 UNITED STATES PATENT OFFICE PLASTICITY CONTROL FOR BRICK MACHINES Alfred F. C. Lotz and Frank C. Mahoney,

Chicago, Ill.

Application May 4, 1942, Serial No. 441,638

10 Claims. (Cl. 2511) The present invention relates to means for controlling and regulating the plasticity of extruded material composed of a solid and aliquid component whose proportions relative to each other are determinative of the plasticity of the extruded material. The invention also relates to the method of controlling the plasticity of such materials, andthereby the speed of its extrusion and the regularity of the extruding operation.

More particularly, the invention relates to a method and apparatus for controlling and regulating the plasticity of an extruded material such as an argillaceous substance-for instance, clayand is more particularly concerned .witha novel method for increasing or decreasing the moisture content of a moving mass of argillaceous material such as clay or the like, so as to maintain substantially constant the plasticity of the material during its extrusion for the purposeof keeping the production substantially uniform.

It has already been proposed in'the past to extrude various types of'plastic material consisting of a solid and a liquid component, respectively, a good example of which operation is the extrusion of clay in the manufacture of bricks and tile. It has been customary to blend a gauging fluid, such as Water, with an argillaceous material, such as clay, kaolin, and the like, and thereafter to extrude this material by means of an auger-type of extrusion press which forces the material through a die from which it issues in a'continuous column which is either horizontally or vertically disposed. There are, however, many other types of extrusion processes in which a mixture of a liquid and a solid material in plastic form is extruded. The familiar example is the manufacture of spaghetti and macaroni in the food industry, while on the other hand extrusion of rubber and other plastic materials for the manufacture of rods and tubing represents another form of operation to which the present invention may be applied. This is particularly true if one of the components of the plastic mixture is a liquid, or at least a sufficiently flowable material to permit of its passing through pipes under the control of automatically or semi-autobrick industry, theaccepted clay-mixing methods and apparatus comprise generally a crusher or grinder for preparing the clay which is to be delivered to the means for mixing said clay with water. Such means are commonly pugmills or the like,the'water or other gaugingmaterial being added to the ground argillaceous material which has been delivered to the pugmill, the, amount- 0f gauging material being predeten, mined to obtain the desired and properdegree ofplasticity. Such a pugmill, for instance, will feed the clay in admixture with its gauging fluid or water to an auger machine, where the clay is -furtherpugged and mixed as a result of the, rotation of the auger, being finally, extruded througha suitablyshaped die toform a column, of the desired shape, depending upon the finishedproduct, such as brick, tile, and the like.

Water or other gauging fluid may be addedto the clay in thepugmill if the clay is too hard and dry, .while on the other hand the amount of gauging fluidorwater is decreased if the clay should-becpme too wet and-too soft. This proc ,esshasbeen termed tempering, andis neces-'.

- desirable consistency and plasticity thereof for the desired and existing working conditions.

Tempering, that is to say the increasing or de-' creasing, of the. amount of water delivered'to the clay'in the pugmill, is usually left to the experience and judgment of the machine operator.

matically controlled valves so that it becomes This method is rather crude, and for eifective operation requires a skilled attendant. 7

However, even though a skilled attendant is operatingor supervising the operationof the pugmill, it occasionally happensthat the consistency i productofluniform plasticity by this oldhandoperated method. k i

In accordance with the present invention, there will, bede j'cribedbotha process, and'anapparatus for automatically controlling and "maintaining the proper plasticity of clay in a continuous process of manufacture. In this method, the tempering-that is, the increase or decrease in the amount of water added at the pugmillis automatically controlled so that manual attention is virtually eliminated once the clay has attained the desired plasticity and the extruded column thereof is moving at the properpredetermined speed. The principle of the operation employed in the hereinafter explained method is based upon the fact that the speed of the extruded col-- umn as it leaves the die of the auger machine is a function of the plasticity of the extruded product.

Keeping the above background in mind, one of the objects of the invention, therefore, is to provide a method for extruding a plastic material composed of a solid and a liquid component whose, proportions relative to each other are determinative of the plasticity of the extruded material which comprises the combination of means for blending the solid and the liquid components, means for extruding the resulting mixture to produce a, moving body of plastic material, means for constantly supplying the solid component, variable means for supplying the liquid component, and means responsive to the speed of the extruded body for controlling the aforementioned variable means whereby the speed of the extruded column is maintained at a predetermined value.

A further object of the invention is to provide means responsive to the speed of an extruded column of clay, which, by the instrumentalities hereinafter more fully described, will actuate through suitable electrical relays various servovalves which in turn control the valves supplying the water or other gauging fluid to the clay or other material.

A further object of the invention is to provide means in an apparatus of the type indicated in the paragraph immediately hereinabove for automatically inactivating the apparatus in case of a shut-down or upon stopping the apparatus entirely so as to avoid flooding of the clay or other material with water. i

A further object of the invention is to provide, in addition to the automatic control, visible means for indicating to the attendant or operator the present condition of the operation so that in case of emergency, appropriate steps can be taken to rectify the difficulty. These means may comprise colored lights, semaphores, bells, and the like.

Other objects of the invention will become manifest from the description and claims which follow hereinbelow.

For example, in the so-called stiff-mud method of making brick and tile, the clay is in a plastic state and is constantly extruded through the die by means of an auger machine. Inasmuch as the clay is, by virtue of its plasticity, more or less mobile, and the pressure of the screw in the auger machine which is forcing the clay through the die will cause the clay between the end of the screw and the extruding die to be under pressure, it will be self-evident that, with a given application of power and a given speed, the rate of extrusion will be roughly inversely proportional to the plasticity of the material. the more easily the material flows, that is to say, the more plastic it is, the more rapidly will it extrude with a given and constant input of power. Conversely, as the material becomes less plastic, it will become more difficult to extrude, and if In other Words,

-' column of material.

the power input is kept constant, the rate of extrusion will obviously diminish.

If a definite plasticity of the clay has been decided upon as standard for the particular operation and the type of product manufactured, then if more moisture is added per unit of clay, it will become softer and more plastic, and hence will be extruded more easily as the pressure between the auger screw and the die will decrease. The result will be an increased speed in the extruded Conversely, if the water is reduced per unit of clay, the plasticity will become less and the clay will become stiffer and harder, from which it follows that the resistance between the auger screw and the die will become greater, thereby reducing the speed of the extruded column. It will thus be seen, therefore, that the speed of the column of extruded clay will vary with the plasticity of the clay, and is in fact a positive function of such plasticity. It will be noted that the relation between the plasticity of the clay and the speed of the extruded column is definite, and that the slightest difference in plasticity will effect a corresponding difference in the extruding speed of the column. That is to say, if a unit of speed per unit of time is taken as standard, then if the clay becomes harder, the speed will be reduced, and if the clay becomes softer, the speed will be increased. In the present invention the speed of the column is utilized for the purpose of automatically governing and controlling the operation of tempering the clay, thereby keeping it at a predetermined plasticity. In other words, the variations of the speed of the column will tend to keep it at a constant predetermined speed.

, The control mechanism employed comprises a roller of pliable material which presses against the moving column of plastic material, thereby deriving its own movement. Self-evidently, the peripheral speed of this roller will be identical with the forward speed of the moving extruded clay column. Inasmuch as the pliable roller is afiixed to a shaft, it becomes possible, as hereinafter more fully described, to employ this rotational movement to effect a suitably constructed governor which in turn controls a lever which normally is in a neutral position between a series of switches when the speed of the column is standard, but which lever will move to close one switch if the speed of the column is reducedthat is to say, when the clay becomes harderand will open this switch when the speed is again standard, thereby returning the lever to its cen-- tral or neutral position. On the other hand, when the speed of the column increases-that is, when the clay becomes soft-this lever will move in the opposite direction, thereby closing a second switch which is employed when the clay becomes too soft. The first switch, of course, Will thereby still remain open. When the column again retains its standard speed, the lever will once more return to its neutral position between the two switches, thus leaving both of them open so long as the extruded column maintains its standard speed. The switches just mentioned are employed to energize certain relays which in turn will not only control the indicator lights or other a indicating means, but also will actuate solenoid operated pressure valves which in turn impart movement through suitable links to valves which are interposed in the water supply line which controls the amount of water that is fed into the pugmill. For example, it might be possible to select a green light as indicative of the normal and desired. operation; of. the apparatus, while using: a red. light if theclayibecomes too hard and: the speed of the column correspondingly decreases, and to use, say, a yellow light when the speedof the column is increased asthe result of too great. plasticity of the clay being? extruded, Self-evidently, other indicating: means, such. as; semaphores or differently-toned bells, might; be: employed. Moreover,v the point at. which this; indication isgiven may be. quite remote from the mill, one system corresponding to the harder andv less plastic condition of the clay andconsequent,

slower speed of the columnof the-extruded clay,

while the other system with its corresponding. similar apparatus will actv when the clay is'more plastic and thereforev is moving at a correspondingly increased extrusion speed. There is also av manually operated cutout switch whichr opens and closes a separate double-pole,- single-throw relay, each pole of which will be normally closed so as to complete the circuit of its corresponding solenoid of the pressure operated control valves and so arranged that when the manually operated.

switch is open, the circuits of: both solenoids will be normally closed, and when the switch is closed, then the double-pole relay is energized and both solenoidswill be. in open circuits, thus rendering inactive both solenoids and their respective pressure valves, pressurecylinders and valves, at the same time, however, allowing the colored-lights,

or other indicating means in the system to function normally.

Better to comprehend. the necessity of the. manually operated switch with its corresponding double-pole, single-throw relay and the solenoids thereby controlled, itmaybe well to explainat.

this point the ordinary daily operation of aclay plant producing brick, tile and the like, In such.

operation, for instance, a water supply line is provided leading to the pugmill, this pipe line supplying more water. to the clay than is normally necessary to give it the required plasticity. A valve whichv normally is at full opening is operated by the pressure cylinder to close the same whenever the clay becomes toosoft, but between. this valve and the pugmill itself there is also interposed. a manually controlled valve which latter can be used so asto control the proper predetermined amount of water which is to be fed. into the clay in the pugmill. In other words, this manually controlled valve is set at a predetermined discharge rate. second pressure cylinder operated valve which is normally closed and is connected with the main water supply line and serves as anauxiliary supply to increase the water supply thatv is fed tothe pugmill whenever the increased hardness of the clay renders it necessary.

Thus ifthe normal amount of-water suppliedto thepugmill is not sufl'icient, and hence theclay becomes too hard, this second valve will be auto matically opened by its: corresponding pressure.- cylinder, whereby a supply of water will be increased over that of. then'ormalflowgthereby inrtroducing. more. water into. the.- clay, rendering it There is also provided a.

operation;..the firsttmentioned: pressure cylinder; operated; valve will; beiopen, as: will also: be the. manually: controlledivalve, which, however, will be set; at' its predetermined opening; 5; Thus'thetwo'pressure cylinder... operated valves will automaticallyclose and open alternately, as conditions :require, thus decreasing or increasing; the amount of water supplied to the pugmilL.

However; when the pugmillan'd auger machine are n'otl-in operation, there will self-evidently be no movement in the extruded column, and conse-- quently there'will be no movement imparted to the pliableroller which is in contact: with the column. Thus a lack of motion will thereforeop,-. erate' just as though the. material had become harder, and the result'will be that the governor" operated lever will close the switch responding to slow'speed conditions of the column, where'- upon; the correspondingrelaywill then energize; its solenoid operated-valve and pressure: cylinder,

thereby opening the auxiliary valve admitting:- more water to the pugmill whileat the same time the green light willbe extinguished: and the red; light will be lit. Under these conditions, ob. 2s. viously due to the shut-down of the pugmill and.

auger machine, the. clay' wouldbe; flooded. It therefore becomes necessary toiwsupply means for; combatting: this condition. Thus. there is pro.- vided a manually-operated cutoutswitch which operatesthe aforementioned double-pole, singlethrowrelay in order to break the circuits in'thesolenoids which. control the. valves, whilejat. the same timelitris necessary to close. the manually operatedvalve in the. main supply line as otherwise water would. continueto flow intothe pug mill. .At the same-time, due to. the circuits in. thev construction, boththe green and yellowlightsv will be extinguished but the red:light.will remain. lit and visible.

Whenthe pugmill and auger machine are again placed in operation, then the manually operated valve inthemain water supply line is opened tothe-predetermined degreeand the red light will continue to bevisible until the column which now beginsv to be extruded has attained its standard speed, whereupon thered light will go out and the green light will go on. When this has been done,, then the manually operated cutout switch is opened, thereby restoring the circuit leading to' the solenoids, whereupon the entire regulating system will again be placed in condition of normal operation so that it may again automatically control thetempering process in the pugmill and auger machine. By co-operation of the correlated apparatus,

briefly hereinabove described, there is therefore accomplished a perfect" tempering of the clay in a novel and efiicient manner.

While there has been-described so. far the useof solenoid operated air valves or pressure cylinders, and the use of air pressure for operating. the same, all controlledby double-pole, singlethrow relays, it is .to be understood, however, that. the invention is by no means to be limited exclusively to their use, and that the said solenoid. operated valves, pressure cylinders, and theair pressure. used for operating. the same may be eliminated, and that the corresponding relays operating the same may, for example, be connected to direct acting solenoids or to electrically 0perated control valves locateclin the main or auxiliary supply lines. Such direct-acting solenoid or electrically operated control valves will then be connected to the. double-pole, single-throw relays more. plastic,-. It'willbe.noticedthat.duringithisi 7m atthepoints; describedafor the; solenoid connec-.

thus eliminating said solenoid operated pressure valves, pressure cylinders, and air pressure for their operation. All this will be more fully understood by reference to a diagrammatic view of the apparatus and system involved in the practice of the present invention. In the hereunto appended drawings,

Figure 1 is an entirely diagrammatic representationv of the system without any regard to scale or precise arrangement;

Fig. 2 is a top view of what is herein termed the prime mover which comprises the control switches and the governor;

Fig. 3 is an elevational side view of the apparatus with the side removed, showing the governor actuated switches, etc., as well as means for supporting the apparatus and for permitting contact with the moving extruded clay column;

Fig. 4 is a side view of the same apparatus shown in Fig. 3;

Fig. 5 is an elevational view of the control mechanism which operates the air pressure valves and the thereby operated water supply valves; and

Fig. 6 is a diagrammatic drawing incorporating the essential features of Fig. 5, plus the wiring diagram which shows its connection with the switch shown in Figs. 2, 3, and 4.

Referring now particularly to Fig. 1, the system comprises various parts and apparatus in cooperative assembly as explained below.

A pugmill 6 is fed in the regular manner with ground clay, and is mixed with water from the main supply pipe 7, which is of suflicient size that it will supply more water than is required. A manually operated valve 8 is placed in the pipe I so as to regulate the normal flow of water to the pugmill 6, and can also be used to stop the flow of water entirely. A second valve 9 is placed between the valve 8 and the water supply to the pipe I. The valve 9 will be normally in open position. When the flow of water from pipe I, regulated by the valve 8, is of the amount required by the clay in the pugmill 6, the mixture of clay and water is churned or pugged .by the screw H1 in the pugmill 6, and forced to the opening ll of pugmill 6, when the mixture will drop into the opening l2 of the auger machine 13. The auger M in the auger machine 13, will further pug the clay and water and drive the mixture through the die I 5, thus forming the column of extruded clay I6, which will move in the direc-' tion shown by the arrow. An auxiliary water supply line It is tapped into the main water supply line 1 at the point I! and placed ahead of the valve 9 in line 1. Line [8 is used to supply additional water to the pugmill 6 in the event that the clay in pugmill 6 becomes hard and has a tendency to increase the pressure inthe auger machine l3 and decrease the speed of extrusion of the column 16. A valve [9 is placed in the auxiliary pipe line It]. This valve is normally closed and operates only when the clay in the auger machine becomes too hard, and supplies additional water to the clay in pugmill 6 so that the plasticity of the clay will be increased, and, due to decreased resistance at the die l5, the speed of the column 16 will be increased to the point of normal extrusion per unit of normally tempered clay per unit of time, equivalent to normal production.

When valve l9 automatically lets more water flow to pugmill B, valve 8 and valve 9 will remain in their normal open position. When the clay tions of the solenoid operated pressure valves,v

inpugmill Gbecomes too soft, and consequently the speed of the column l6 increases, the valve 9 will automatically close to decrease the water supply to pugmill 6, thereby decreasing the plasticity of the clay in pugmill 6, so that the speed of the column 5 will be decreased toward the point of normal extrusion per unit of prescribed time. During this operation of valve 9, the valve 8 will remain 'open to the degree at which it has been set and-valve l9 will remain closed.

When column I5 is being extruded at normal requirements, valve 9 will be in full open position and valve. [9 will be closed.

Having thus far described the apparatus and its operation, there will now be described in detail the balance of the apparatus which in connection with the above forms a complete automatic tempering system.

The moving column 16 of plastic material (clay) actuates a roller 20 made of pliable material in order to effect good contact and to insure a peripheral speed equal to the speed of the column [6. This actuates the prime mover broadly designated by the reference numeral 200 which is electrically connected with the valve control unit broadly designated as 300 by means of a multi-wire cable 4. This control unit is described in connection with Figs. 5 and 6.

Referring now primarily to Figs. 2, 3 and 4 which illustrate the details of the prime mover 200, it will be seen that the roller 20 is rigidly fastened to the shaft 2| by being held under pressure against the colla 22 which is an integral part of the shaft 2|, the necessary pressure being obtained by the nuts 23 and 24. The shaft 2! rotates in the bearings 25 and 26 provided in the frame 21. The shaft 2| is prevented from lateral displacement by collars 28 and 29 which are rigidly fastened to the shaft 2|. A means for transmitting the rotary motion of shaft 2| to the coordinating mechanism of the governor is provided by the pulley 30 which is fastened to shaft 2| and rotates with same. A continuous belt 3| imparts th motion of pulley 30 to a pulley 32, which is fastened to the shaft 33. It is to be understood that although a pulley transmission is shown, any other method of transmitting motion may be employed, such as a train of gears, sprocket wheels and chain, and the like. Shaft 33 rotates in the bearings 34 and 35 in the frame 21. Lateral movement of shaft 33 is prevented by the fixed governor head 36, which is a square block with the shaft 33 running through its center. Block 36 is rigidly fastened to shaft 33. The collar 31 is also fastened to shaft 33 to prevent lateral motion. Two governor balls 38 and 39 are placed on opposite sides of shaft 33 and are held equidistant from the center of shaft 33 by links of equal length 4|], 4|, 42, 43, 44, 45, 46 and 47, and are symmetrically placed and loosely connected to the fixed head 36 at pivot points 48 and 49 and to the governor balls 38 and 39 at pivot points 50 and 5| and at pivot points 52 and 53. The corresponding links are connected to'a movable crosshead 54.

The movable crosshead 54 consists of a square block having a square shoulder at each end, and the space between said ends is round, forming a cylindrical section. A round hole runs through the length of the crosshead to permit of its being mounted on shaft 33, and so arranged that cross head 54 will move freely on shaft 33. When the governor balls 38 and 39 as a result of centrifugal force change'their distance from the center of shaft 33, the crosshead 54 will be moved to the lefties viewedzimliigjZ) when :the:;sp.eed becomes I ssreater, :or -;to :the :right when the speed -is less than :the prescribed predetermined standard :speed. The ,crosshead 154 :revolves .between the :roller 55,:and roller. 56.,arranged'to revolve freely OX1 their .respective :pins :51 and 58, forming 'a .part of levers 15.9 :and 60 respectively, fastened rigidly on shaft 6| and in line-witheachrother. Shaft 6| is supported in the uprightzmembers of frame .21 and revolves freely therein.

.:A :switch operating lever 62 is also :rigidly :fasstoned to .shaftSI and in line ,With levers 59 and 126.0. Apin :63 is .tightly'fastened to lever EZiand constitutes an entity with'the same. To pin 63 is fastened; a regulating spring .64, the other end iofwhichisfastened zto regulating screwi65, an end of which engagesdn the movable ,nut :fifisup- .ported :on and. movingfreely .on a projection of the frame 21.

When the governor balls;-38';and i39 are-in neutral i operating position, the tension 1.011 spring 64 cisradjustedby .rotatingrnut66so as to bring the =:-swit,ch operating lever 62 into neutral position, =thus .corresponding to .the normal predetermined :speed :of tthe :column :I16. The tension of spring 54. also.reacts:on rollers--55 ,and 56 to press the .same on fthe shoulder of crosshead 54, thus causing crosshead .54 to be movedtotheright (as @viewed in .Fig. 2) whemthe centrifugal action of :theqgovernor .balls is lessened on account of the ,decreased .speed .of column I 6. Adjustable stops liland i68-1are;placed on either side of crosshead 5l zonishaift 33-tolimit the travel of crosshead 54.

illwo ysingle-pole single-throw snap switches .69 and I0,-pf. standard design, are fastened to frame 21 in right :and left hand positions,:their corresponding,operatinglevers -11 and I2 beingpivoted .onztheir respective pivot points 'l3 and I4. Levers 1 I and :12 are electrically insulatedffromtheparts 'forming.the=.electrical-contacts 15 and I6 inswitch 69 and-contacts TI and 18 in switch I0. Operating switch levers Til and "I2 rareplaced so "that they will both be in mechanical contact with movable lever 62 when the, lever 62 is in neutral position due to the normal speed of column I6 so that thus zboth switches .69 :and 10 will be in open circuit. When .lever 62 moves tothe right "(asviewed inFigam ,.switch 'I0"will be closed and .switch69 willbe'open. When lever'62 moves to the left, switch 69 will be-closed and switch 10" will be open. When lever-62 [returns to neutral position :both switches 69 and '10 will be open. Pins I9 :and 9.0 are .fastened to the lower-part of frame Q21 :and pass loosely through a supporting :bracketfil. rPiIlS .19 and 80are held-in place :by cotter .pins 82 and -83 ,respectively. Compensating springs '84 and .85 are ;placed between :the frame 21 and bracket 8| to balance the weight -:above springs '84 and 85 and allow adjustment =ofthe pressure of roller oncolumn IB'through theupward ordcwnward movement of bracketal .relative tocolumn l6. Bracket Blisheld-in horiizontalposition .by clamp 86 and Ubolta-BJ. Clamp 206 ,is ;held to the vertical supporting .pipe '88 .by .U bolti89. Clamp :86 .is adjustable up and down aonpipe 268 so as to obtain ,the proper pressure of =rol1er.-20 on column .16. Pipe is fastened to a baseboard .90 .in iaiconventional .manner. Baseiboarcl 90 rests on the floor and keeps the :pipe .88 in gar-vertical position.

..A cover -.9I is fastened to frame .21 so as en- :tirely .to enclose =all vof the parts supported by name-21. On-onesfacec'ficover 9I are-fastened a single-pole sin le-throw switch 92, of .convenitiona lid si n, and a :multicontact :maleplug '93 I with :protrudingcontacts 94, 95, .96, 91 and-:98. .In order .to facilitate the path of the electric-current passing through .the contacts 94, 95, 96, 9! and 98 .of the maleplug 93, the wires connecting i'tc'these .contacts are given the same numbers :as the contacts.

The valvecontrol mechanism shown in Fig. 5

consists of a mounting board 99 on which are rigplace in the plant and at any distance fromthe prime mover 200, depending on the desired length of the connecting cable. The various pieces of .apparatusfastened .to thecontrol panel 99 consist of .a single-pole double-throw power switch I00 whosecompanion contacts IM and I02 on one side are normallyopen. and thecontacts I03and [Mon theother side are valso'normally open, and

whencontacts IOI and I03 are simultaneously.de

.pressedtomake contact with I02 and I04 respectively, thecircuits leading to the switch Will-be completed. It is to be noted that each piece ,of apparatus shown in Fig. 5,.isofstandard commercialdesign and therefore does not require a detailed description and is consequently depicted inpurely diagrammatic form. A series of visible indicator lights of diiferent colors is mounted .on board 99rasfollows: a green light I95 hows normal operation, a red light I06 shows decreased speed of column I6, and a yellowlight I01 shows increased speed of column I0. When green light I05 is visible, lights I06 and I0! are out. When red light I06,is on, lights I05 and I0! areout, and whenyellow light I01 is on,.lights I05 and I06 are out. I08 is a double-pole single-throw relay consisting of a stationary contact I09,.normally in closed contact with movable contact II0, a stationary lower contact III which is in normal open position with reference to contact I I0, and an electromagnet I I2 which, when energized, will act on contact IIO, closing the circuit with contact III, and when de-energized will open contact between I I0 and III, and close contact'between H0 and I09. Contact H0 is springoperated to normally be in closed circuit with contact I09. Relay H3 is a duplicate of relay I08 with its corresponding upper contact II14, movable contact I I5, lower contact I I6 and electromagnet 1.

There is also provided a double-pole, singlethrow relay I'I8 whose upper stationary contact H9 is normally closed With movable contact I20, and -upper stationary contact I2I is normally closedwith movable contact I22. Contacts I20 and I22 are insulated from each other on base I23 towliich is fastened a magnetic core I24. Contacts I20.and 122, base I23 and core I 24 comprise a working'unit which isheld against contacts I I9 and I2I byspring action. An electromagnet I25,

when energized, will pull down'the unit comprised of I20, I22, I23, and I24, and will open the respective circuits between H9 and I29 on one side exhaust port I28 is normally open, and supply port I29 is always open. A piston plunger I30 in its down position normally closes port I21 and opens port I28. When solenoid I 3| is energized, plunger I30 is pulled up and port I2! is open to pressure, port I28 is closed and pressure from port ;I;2'I .is transmitted to port I29. When sole- :noid [311s de-energized, plunger I30 drops down 4 which has a branch pipe I 31 connected to it.

Pipe I3! is connected to any source of compressed air to supply pressure to'valves I26 and I32. A standard socket I38 is supplied so that an electrically operated air compressor may be connected to the valve control system to actuate the same. Pipe I39 connects with port I29 of valvel26 and also connects with pressure cylinder I40 containing piston MI and piston rod I42 which extends through the top of cylinder I 40 I and is connected with the operating arm of valve I9 by means of the link I43. A regulating exhaust valve I 44 is placed at the top of cylinder I40 and may be opened or closed to regulate the exhaust from cylinder I40. thereby controlling the speed at which piston I 4! will ascend by more or less compressing the air in the cylinder, and conversely will regulate the downward stroke of" piston MI by the intake of air in slower or faster degree. The piston MI is returned to its normal down position by gravity.

There is also an air pressure cylinder I45, similar to cylinder I40, which is connected to port I35 of valve I32 by means of. pipe I46. The piston rod I4'I of cylinder I45 is connected to operating arm of valve I9 by means of link I48.

Having described in detail all the mechanical and electrical devices used in the entire system,

there now follows a description of the consecutive actions of these devices when the complete system is in actual operation. Starting with the column I6 running at normal operation and there fore with the control system in neutral position, the electrical current from the power wires I49 and I50 will pass from wire I49 to wire I5I through switch I00, whose contacts are normal-- ly closed, through contacts I03 and I04, to wire I52, and will connect with the yellow light I81 and the movable contact IIO of relay I08 from contact I I0, through stationary contact I09 of relay I08 to wire I 53,, through green light I05 to wire I54, through upper stationary contact II 4 to movable contact II 5 of relay II 3. Contact II5 connects with wire I55 which connects with return wire I56 through closed contacts I02 and IOI of switch I to wire I51 to the return power.

wire I50. Thus it will be seen that relay I08, green light I 95 and relay II3 are normally in series so that if either relay I08 or I I3 is actuated, the green light I will be disconnected and therefore not visible. hard and the speed of column I6 decrease, the centrifugal force of governor balls 38 and 39 will become less and will be overcome by the tension .on spring 64 which causes the arm 62 topress against lever I2, thus closing contacts 91 and 98 IIO from I09 of relay I08 and close contact IIO with contact I I I of relay I08. The current to the Should the clay become r to close port I21 and open exhaust port I28, thus green light will thus be disconnected. The current'from I52 will now pass through movable contact I II] to contact III connected with wire I68, through red light I06 to wire I55, to wire I56, through contacts IIlI and I02 of switch I80 to wire I51, to return power wire I50. Thus it will be seen that red light I06 will now be visible and green light I05 will not show.

The solenoid I3I of three-Way valve I26 is connected by wire I6I tomovable contact I20 to stationary contact I I9 of relay I I8, and from contact II9 to wire I62 which connects to wire I60. The other end of solenoid I3I connects with wire I63. Thus it will be seen that solenoid I3I is connected in parallel with red light I06 and will be actuated at the same time that red light I06 is made visible. The current for solenoid I3I will come from wire I62 through contacts H9 and IE0 of relay IIB to wire I6I through solenoid I3I to wire I63 which connects with wire I59.

When solenoid I3I is energized, the plunger I30 will be pulled up, opening port I21 and closing port I28 of valve I26. The air pressure in pipe I37 will now pass through pipe I36 to port I21 to port I 29, through pipe I39 to pressure cylinder I40, acting on piston MI and forcing same up to act on connecting link I43 and then on lever arm of valve I9, thus opening valve I9 and allowing more water to go to pugmill 6. This water will flow from pipe 'I to pipe I8 and will be in addition to the normal water supply from pipe I. With the addition of more water to pugmill 6, the clay will become softer and the speed of column will become greater until it again reaches its normal speed. The centrifugal force of governor balls 38 and 39 will increase to the point where the tension of spring 64 is balanced and lever 62 is brought back to neutral position. when contacts 91 and 98 of switch 10 will be opened and all circuits affected by contacts 91 and 98 of switch I0 will become dead. The plunger I30 of valve I26 will then return to normal position and close port I21, thus shutting off thepressure from pipe I36 and opening port I28 to the atmosphere. Piston I4I will then return to normal position by gravity and exhaust the air through pipe I39, port I29 and port I 28. When piston I4I moves down it will close valve I9, thus shutting oir the auxiliary water supply from pipe I8 to pugmill 6.

When lever 62 returns to normal position, solenoid of magnet II2 will be de-energized and contacts III] and I II will be opened, breaking the circuit to red light I06, and contact I II) will again connect with contact I09 and thus re-establish the current through green light I05 and the whole system will again be in neutral or normal condition.

Should the clay in auger machine I3 become too'soft, the speed of column I6 will become greater and the centrifugal force of governor balls 38 and 39 will increase and overcome the tension of spring 64, thereby causing the lever 62 to close the contacts 96 and 91 of switch 69, causing the current to flow from wire I58 to 91, through contacts 91 and 96 in switch 69, along 96 through solenoid of magnet II1, the other end of said solenoid connecting to wire I55 and then to wire I56, through contacts 40I and 402, and wire I51 to return power wire I50. This will energize magnet II I, pull down contact "5, and open the circuit between contacts H4 and H5, thus extinguishing green light I05. At the same time contact I I5 will connect with contact II6, connected to wire I64, which in turn connects c-tozyellow light I01 and contact:I2Ii:vof1relay.::II58. -.Qontact I22 :of; relay Jl I18 -;connects wlthzzmovable :contact .I'23*to wire II 675, to-tsolenoidLin valve 1.32 :from .solenoid to wire I fifinwhichoconne'cts tot-one sideof;socket.l38,i and tovwire IBIwhich-connects 1 :with wires 195 and A11. The :other :contact "of socket 11-38 connects to wire I 68,- :andtthis connects to wire'l55. When solenoid. in valve I 32 ris energized, the 'plunger in rvalve I32 awill .openiport I33 and close .portI'34. 1.This.will.-now\allowi'fluid under pressure from :pipes I31 and I36 Lto pass through valve I32 'to' port I135, pipel lfi toicylinder I45, and'cause piston incylinder I45 to' bepushed zupward. .Piston rod I41 o'f'va1ve I 45 is connected through link I48 to operating :arm of valve 9 in pipe I. The upper: movement ofupiston'ro'd I41 \willthus close valve 9 and decrease thenormal flow of water from-pipe 'I topugmill -G. Meanwhile valve I9 is closed. Decreasing the'water rsupplyzto 'pugmill 6 'will 'decrease the plasticity "of'the clay in the pugmilland cause the same :tol'become :harder, this also applying "to-the clay in 'auger'machine I3. The-speedof column IE --will thusbe retarded and-when'column IGis again 1 at normal speed; lever "62 'will-again'bein neutral position. This will open contacts in sWitchIf-GB, said contacts being connected to wires 95 and 91,.and the whole system will again be in normal or neutral .operating condition and the yellow .light'will be cut out-and the green light/become :visiole. vThe plunger of valve -I3-2-wil1 now fall down :and ClOSEJPOI't I33 and open' exhaust port I34. thus removing the pressure to the piston in valve I45 and allow-same-toreturnto normal -downtposition by:gravity. This will open valve9 the clay would be flooded and become too soft i toloperate satisfactorily. To prevent'this, the hand valveB in pipe 1 should be closed 'and'swltch :92 on prime --mover (Fig. 2) should be closed zthrough the contacts connected to wires -94"and =95. pass through wire I69, through'magnet-coil I25 to wire I'Il'. which connects with 94 through closed contacts'of switch92, to wire 95, to wire I58, to wire I52, and thus'back' to power wire I50. This will energize magnet I25 which will pull down armature I24 and the contacts I and I22, thus breaking the circuits of the solenoids of valves I and I32, making same inoperative.

When the auger machine I3 and the pugmill 6 are again placed in operation and column I5 attains normal speed, the green light will again appear and witch 92 is opened, as is also valve 8. Thus the entire system will again be in neutral position and normal automatic operation.

It is of course evident that various modifications may he devised regarding the details of construction of various parts as Well as the embodiment of the invention as a whole. The invention may be used in connection. with the preparation and manufacture of widely difierent materials apart from its use as described in the preparation of clay. Many other changes may be devised, either in the details of the parts or in the operation of the entire system to accomplish the end desired through the principles de- This will cause current from wire I56 to scribed. We,thereforeiidesireit to :be understood that what We have described and showniis intended-torepresent one embodiment for thepurpose of teaching others how the invention may be applied to practical use, but notfor thepurpose of indicatin the limitations of the invention either in its details or in its entirety.

"We have defined in the following .claimswhat We believe is new in the art, and we intend to use and to apply the invention within the scope and meaning of these claims.

"We claim'as our invention:

1. In an apparatus for extruding plasticclay bodies composed of clay and water, means for hlendingthe clay and water to produce a plastic extrudahle clay mixture, means for extruding said mixture to produce a moving column of plasticclay, means for constantly supplying clay,

variable means for supplying water for admixture with said clay, and. means responsive to variations in the speed-of-the-extruded clay column to regulate the means supplying saidvJate'r, whereby the speed. of the extruded column of cla is maintained substantiallyat a predetermined value.

2 In an apparatus for extruding plastic-clay bodies composed of clay and water, means for tile theclay and'water'toproducea plastic ex u-dahle clay mixture, means for extruding said mixture to produce a moving column of plastic clay, means for constantly supplying clay, means for supplying Water foradmixture with ond 'rneans will. become 'actuated'to supply'ad'dh tional water to said clay.

3. A clay tempering aurl'extruding system comprising the combination of means for plunging clay with water means'ior xtruding said plunged clay into'the form ofa' moving column of clay, means for supplying water for the plunging oper- 'ation, 'means for supplying auxiliary water for admixture with "said clay, means for throttling the first mentioned means of supplying water.

means responsive to a decrease int-he speed of the extruded column to regulate the auxiliary supply, means responsive to an increase in the speed'of the "commute actuate said throttling means." and means for-inactivating both'the' auxiliary and the throttling means when the column is at rest.

4. In a system for preparing plastic material having a mixing machine and an extrusion machine disposed in serial relation, the combination of a fluid supply means co-operating with said mixing machine for tempering the material supplied, to said extrusion machine, and a control apparatus driven by and dependent upon the speed of the extruded column of plastic material frorn the extrusion machine, said control apparatus co-operating with the movement of the extruded column of plastic material to regulate the fluid supply to the mixing machine.

5. In a system of preparing plastic material having a mixing and an extrusion machine disposed in serial relation, the combination of a supply means of fluid material to said mixing machine for tempering said plastic material, and a control apparatus responsive to the movement of the column of extruded material for automaticallyproportioning the fluid supply to the material in the mixing machine.

6. In a system of preparing plastic material having a mixing machine and-an extrusion machine disposed in serial relation, the combination of a means of fluid supply to the material in the mixing machine, and an automatic electromechanical control apparatus deriving its motion from the speed of the extruded column from the extrusion machine, the variations of speedof said control apparatus depending upon the variations of the speed of said extruded column, and automatically controlling the fluid supply to the material in the mixing machine and extruding machine, increasing the fluid supply to the mixing machine when the speed of the extruded column decreases, and decreasing the fluid supply to the mixing machine when the speed of the extruded column from the extruding machine increases.

7. In a system for preparing clay having a pugmill and an auger machine in serial relation, the combination of a mean of water supply to said pugmill for tempering the clay being fed to the auger machine, a responsive control apparatus actuated by and dependent upon the speed of the extruded column of clay, said control apparatus being in neutral position when the column of clay is being extruded at a predetermined speed, and causing the water supply to the clay in the pugmill to be increased when the speed of the extruded column is decreased from the predetermined speed, and decreased when the speed of the column of extruded clay is increased,

and means for causing the responsive control apparatus to return to neutral position when the extruded column again is at the said predetermined speed.

8. A system for preparing clay, comprising a pugmill fOr treating and feeding tempered clay to a therewith correlated auger machine, a means for supplying water to said pugmill, a responsive rotatable regulator actuated by and dependent upon the speed of the extruded column of the auger machine, a pressure lever actuated by the movement of said rotatable regulator, said pressure lever being in neutral position when the extruded column is moving at a predetermined speed, movable contact means operated by movement of said pressure lever, stationary contact means in juxtaposition with movable means, said contact means being in open position when said pressure lever is in neutral position, and when the column from the auger machine is moving at a predetermined speed, said pressure lever closmg one set of contacts when the speed of extruded column is decreased, and through correlated electromechanical valve means increasing the water supply to the pugmill, said pressure lever opening said contact means when said pressure'lever returns to neutral position, said pressure lever closing a second contact means when the speed of the extruded column is increased, and through correlated electromechanical valve means causing a decreased supply of water to the pugmill, said pressure lever returning to new tral position when the extruded column has regained its normal predetermined speed, when said contact means and said correlated electromechanical valve means will become inactive, whereby the plasticity and the speed of the extruded column at the point of extrusion will be controlled.

'9. In a control system of the type described, the sub-combination of a control mechanism comprising a supporting frame, two hafts rotatably supported thereon, a rotatable member affixed to one of said shafts for contacting a, substantially constantly moving bod of plastic material, means connecting said shafts so as to transfer motion from one to the other, a governor on one of said shafts, means operated by said governor to actuate a lever in one or the other direction, two electrical switches positioned one on each side of said lever, said lever being capable, under the influence of said governor, of contacting either of said switches alternately and of remainin in a neutral intermediate position between said switches when the speed of rotation is at a predetermined value, electrically operated valves connected with said switches, and a power-supply means for actuating the said valves when their corresponding circuit is closed by means of said switches.

10. Method of maintaining substantial y constant the speed of extrusion of a body of plastic material composed of a solid and a, liquid component which comprises substantially constantly blending said components at a predetermined rate to eventuate said plastic body, extruding said body to produce a movin column thereof, employing the variation in the movement of said body to control the supply of said liquid so as to increase it as the speed of movement decreases, and to decrease it as the speed of movement increases.

ALFRED F. C. LOTZ. FRANK C. MAHONEY.

CERTIFICATE OF CORRECTION. Patent No. 2,5L o,675. February 1, 19th.

ALFRED F. c. LO'I'Z, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 7, second column, line 51, claim 5,- for "regulate" read --actuate-; line 55, for "actuate" read --regulate-; and that the said Letters Patent should, be read with this correction therein that the same ma; conform to the record of the case in the Patent Office.

Signed and sealed this 25th day of April, A. D. 19%.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

